documentary vs podcast

documentary

noun
  • A film, TV program, publication etc. which presents a social, political, scientific or historical subject in a factual or informative manner. 

adj
  • Of, related to, or based on documents. 

  • Which serves to document (record and:or illustrate) a subject. 

  • Presented objectively without the insertion of fictional matter. 

podcast

noun
  • An individual episode of such a programme. 

  • A programme, especially an audio programme, produced on a regular basis, delivered over the Internet in a compressed digital format and designed for playback on computers or portable devices such as mobile phones. 

verb
  • To deliver a programme, especially an audio programme, over the Internet on a regular basis for playback on computers or portable devices such as mobile phones. 

  • To deliver (information) in the form of a programme, especially an audio programme, over the Internet on a regular basis for playback on computers or portable devices such as mobile phones. 

How often have the words documentary and podcast occurred in a corpus of books? (source: Google Ngram Viewer )